1. Field of the Invention
The present invention relates to a vertical calibration method, and more particularly to a vertical calibration method for a wire cut electric discharge machine to easily measure the vertical position of the wire so as to be able to make the vertical wire calibration for the wire cut electric discharge machine before cutting.
2. Description of Related Art
In general, the well known technique available in the market to calibrate a wire cut electric discharge machine is disclosed in U.S. Pat. No. 4,559,601; U.S. Pat. No. 4,703,146; U.S. Pat. No. 4,713,517; U.S. Pat. No. 4,673,788; U.S. Pat. No. 4,931,614 and U.S. Pat. No. 5,006,691. Referring to U.S. Pat. No. 5,006,691; the patent discloses an automatic correction operation which is carried out by using the correction factor to correct the distance of the upper and lower wire guides from a reference table, which have been calculated as necessary for controlling the movement of the wire guides. Therefore, a series of subroutines are carried out to determine whether the wire guides are perfectly perpendicular to the reference surface.
In U.S. Pat. No. 4,931,614, developed another calibration method for a wire cut electric discharge machine in combination with a device. The device determines and sets an attitude of the wire electrode according to a total number of times of contact of one of upper and lower contact members of a perpendicularity detector in contact with the wire electrode and a ratio of a number of times of contact only of the upper contact member with the wire electrode to a number of times of contact of only the lower contact member with the wire electrode.
With reference to FIGS. 5 and 6, a conventional calibration device (90) includes two detectors (91,92). A wire (53) is securely extending between the upper wire guide (51) and the lower wire guide (52). The wire (53) has to be perfectly vertical to reference surface before machining. Using the calibration device (90), the upper wire guide (51) and the lower wire guide (52) are moved to contact with both the detectors (91,92). After engagement between the wire (53) and the detectors (91,92), signals so generated are sent to control system (not shown) to determine whether the wire (53) is perpendicular to the reference surface. If the control system receives two signals simultaneously, the wire (53) is perfectly perpendicular to the reference surface.
In order to precisely determine whether the wire (53) is perpendicular to the reference surface, the precision of both the detectors (91,92) is highly requested, which causes the manufacture cost and maintenance fee skyrocketing high. Also, the calibration method is very troublesome.
To overcome the shortcomings, the present invention tends to provide an improved calibration method to mitigate and obviate the aforementioned problems.
The primary objective of the present invention is to provide an improved calibration method to quickly calibrate whether the wire in the wire cut electric discharge machine is perpendicular to the reference surface.
In order to determine whether the wire is perpendicular to the reference surface, the procedure of the present invention includes:
marking down the original position of the upper wire guide of the wire cut electric discharge machine;
moving the upper wire guide backward for a distance (m) and then marking down the second position of the upper wire guide;
moving the wire horizontally until the wire contacts with the detection unit and then marking down the third position of the upper wire guide and measuring the distance between the second position and the third position of the upper wire guide;
returning the top wire to the second position and then lifting the upper wire guide for a distance (k) and marking the fourth position of the upper wire guide;
moving the wire horizontally until the wire contacts with the detection unit and then marking down the fifth position of the upper wire guide;
returning the top wire to the last position and then lifting the upper wire guide for another distance (k) and marking the sixth position of the upper wire guide;
moving the wire horizontally until the wire being contact with the detection unit and then marking the seventh position of the upper wire guide and measuring the distance between the sixth position and the seventh position; and
calculating the vertical position of the top wire and the distance between the upper wire guide and the lower wire guide using the principle of triangle.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.